Weanling-aged rats demonstrate a burst of activity after nursing, which in turn, stimulates their initial exploration and subsequent ingestion of solid food. Little is known about behavioral processes that are important to first ingestion of solid food among human infants. The present experiments are designed to contribute to the understanding of the human infant weaning process by determining whether weanling-aged human infants are also more likely to interact with their environment and ingest solid food following a milk feed. To this aim breast-fed infants interaction with food and nonfood environmental stimuli will be examined at different times in relation to breast-feeding. Controlled laboratory tests will measure the infants acceptance of a novelly-flavored cereal mixture and their motor and behavioral response to a mobile immediately before and immediately after breast-feeding. It is expected that infants will show greater behavioral readiness to ingest the novelly-flavored cereal mix and will be more interactive with the environment when tested after compared to before breast-feeding. This work is expected to contribute to understanding of the weaning process, and be of assistance to health care professionals when making recommendations regarding methods for introducing solid food to infants. Future research directions are discussed which involve: 1) delineating the mechanisms by which post-suckling activation may be mediated; and 2) comparing post-suckling activation in breast-fed versus formula-fed infants.